Captured CO2 Could Fuel a Giant Underground Battery

A massive carbon battery could be used to store energy from renewable sources, such as wind and solar. Continue reading →

Carbon dioxide generated by burning fossil fuels and other human activities is a big problem, when it comes to climate change. But researchers say that it actually may be possible not only to capture and store CO2 in the ground, but to transform it into the equivalent of a battery that would store energy from renewable sources and solve the supply fluctuations that hinder them as a replacement for coal.

A international group of scientists, which includes Lawrence Livermore National Laboratory researcher Tom Buscheck, recently proposed a design for such a carbon battery in a paper presented at the European Geosciences Union general assembly in Vienna. The idea is to store energy generated by renewable sources such as wind and solar power when electrical demand is low, and then tap into it at peak times. (The system could also store energy generated by burning coal as well.)

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That ability to store renewable energy would solve two problems at once, researchers explained in a New Scientist article. It would help create an economic incentive for carbon capture and sequestration, which they said has been slow to develop because it doesn't make money for power companies.

Second, the storage would make renewable energy available even at times when the wind dies down or the sun is behind clouds.

The process takes C02 that's been put in supercritical form - that is, a fluid state where it has both gaseous and liquid properties - and injects it into brine, or salty water, in rocks about a half-mile to 3 miles under the surface. Some of the brine is displaced toward the surface, where it can be heated with the surplus electricity and then circulated back down into the rocks to store the heat.

Back inside the Earth, the heated brine makes the carbon dioxide expand. The C02 can then be used to spin special turbines, which are 50 percent more efficient than ones driven by conventional steam.

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Buscheck said such a system could store 8 million tons of carbon dioxide each year for 30 years - about the same amount that a coal-burning power plant generates.

In 2013, Buscheck and colleagues also developed a system that would utilize sequestered C02 to help draw in underground heat to boost geothermal power generation.

A coal power plant at Michigan State University provides heat and electricity.

The effects of global warming are frequently projected decades into the future, but two recent reports -- one from the

U.S. Global Change Research Program

and the other

from the U.N.

-- put into sharp focus visible consequences of our warming planet. An increase in temperature, extreme weather, loss of ice and rising sea level are just a few of changes we can measure right now. Let's take a look at some of the most concerning trends.

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Glaciers are shrinking worldwide and permafrost is thawing in high-latitude and high-elevation areas, reports this year's Fifth Assessment Report from the Intergovernmental Panel on Climate Change.

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Only a few extinctions are attributed to climate change, reports the IPCC, but climate change that occurred much more slowly, over millions of years, caused major ecosystem shifts and species extinctions. Land and sea animals are changing their geographic ranges and migratory patterns due to climate change.

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Sea level around the world has increased by about 8 inches since 1880, reports the 2014 National Climate Assessment, which projects a 1 to 4 foot rise by the end of the century.

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Excess CO2 is dissolving in the ocean and decreasing the pH of seawater. The ocean is about 30 percent more acidic than it was in pre-industrial times. More acidity in the oceans makes it harder for animals to form calcium carbonate shells and skeletons and erodes coral reefs.

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The probability of a Sandy-like storm deluging New York, New Jersey and other parts of the East Coast has nearly doubled compared to 1950, according to the American Meteorological Society. Even weaker storms will be more damaging now than they were 10 years ago because of rising sea levels. Superstorm Sandy cost the nation $65 billion, according to the 2014 National Climate Assessment, and 2012's Hurricane Isaac cost $2.3 billion.

The global sea level rises along with the temperature for two major reasons. For one, heat causes water to expand, which causes the existing water to take up more space and encroach on the coast. At the same time, ice at the poles and in glaciers melts and increases the amount of water in the oceans.

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Across the United States, heavy downpours are on the rise, especially in the Northeast and Midwest. Increases in extreme precipitation are expected for all U.S. regions, reports the 2014 National Climate Assessment.

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The most recent IPCC report states with "very high confidence" that current climate-related extremes like heat waves, droughts, floods, cyclones and wildfires are showing that countries around the world, at all development levels, are significantly unprepared. The American Meteorological Society estimates that approximately 35 percent of the extreme heat in the eastern United States between March and May 2012 resulted from human activities' effects on climate. The AMS warned that deadly heat waves will become four times more likely in the north-central and northeastern United States as the planet continues to warm.

NASA: Global Warming Goes On